1. Field of the Invention
The present invention relates to an apparatus and method for driving a light emitting diode (LED).
2. Description of the Related Art
LEDs are widely used as a light source of a backlight unit in a liquid crystal display (LCD) device to enhance a color reproduction and a high brightness.
The backlight unit includes an edge type and a direct type according to a method of using a light source. In the edge type, a light source is installed on a side of a light guiding plate. The edge type is applied to a relatively small sized LCD device such as a computer monitor. The direct type is applied to a relatively large sized LCD device such as larger than a 20 inch monitor.
The backlight unit includes a plurality of arrays for lights of red, green, and blue LEDs. Driving pulses are supplied into red LED, green LED, and blue LED, respectively. A white light including red, green, and blue lights is used as a light source.
As illustrated in FIG. 1, the driving pulse is outputted to each LED at the same predetermined interval T. Therefore, the red, green, and blue LEDs are simultaneously turned on or off. However, all the LEDs in the backlight unit are turned off or on simultaneously. Accordingly, numerous compound harmonics occur such that wave noise in an output screen of an LCD panel of FIG. 2 is generated. The wave noise distorts an image in the LCD panel.